OFFSET
0,8
COMMENTS
Alternative name: Number of integer partitions of n that are either empty or have smallest part not dividing all the others and greatest part not divisible by all the others.
EXAMPLE
The a(0) = 1 through a(12) = 7 partitions (empty columns indicated by dots):
() . . . . (32) . (43) (53) (54) (64) (65) (75)
(52) (332) (72) (73) (74) (543)
(322) (432) (433) (83) (552)
(522) (532) (92) (732)
(3222) (3322) (443) (4332)
(533) (5322)
(542) (33222)
(722)
(3332)
(4322)
(5222)
(32222)
MATHEMATICA
Table[Length[Select[IntegerPartitions[n], #=={}||!And@@IntegerQ/@(#/Min@@#)&&!And@@IntegerQ/@(Max@@#/#)&]], {n, 0, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Apr 15 2021
STATUS
approved